1. Field of the Invention
The present invention relates to induction of apoptosis by a 2-nitroimidazole derivative, and more particularly to a method for inducing apoptosis of cancer cells by this compound to treat a cancer.
2. Description of the Background Art
Medical treatments for cancers are roughly divided into radiotherapy and chemotherapy. In recent years, induction of apoptosis of cancer cells has been known to be an important factor for treatment of cancers in both radiotherapy and chemotherapy. An attempt to treat a cancer by inducing apoptosis of cancer cells is going to be performed.
On the other hand, 2-nitroimidazole derivatives represented by the following general formula (1): ##STR2## wherein R represents an alkyl, alkenyl or alkynyl group substituted by 1 to 3 hydroxyl groups, have been already known to be useful for cancer radiotherapy as radiosensitizing agents for hypoxic cells (EP 312858, WO91/11440). As described in Whillans, D. W. et al., Radiat. Res. 62(3), 407-421 (1975), the radiosensitizing effect of these compounds on the hypoxic cells is said to be based on the mechanism that these compounds distribute toward the hypoxic cells, which generate oxygen radical to only a small extent by irradiation because they are hypoxic, and their nitro group reoxygenates the hypoxic cells to enhance the radiosensitivity of the hypoxic cells. However, what action these compounds exert on apoptosis of cancer cells has not been known at all.